School of Mathematics and Physics  UQ eSpace
http://espace.library.uq.edu.au/
The University of Queensland
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Anisotropybased performance analysis of linear discrete time invariant control systems
http://espace.library.uq.edu.au/view/UQ:1481
20060404T14:01:19Z
Diamond, P; Vladimirov, I; Kurdjukov, A; Semyonov, A

Anisotropy in swave BoseEinstein condensate collisions and its relationship to superradiance
http://espace.library.uq.edu.au/view/UQ:341250
20141007T00:19:51Z
Deuar, P.; Jaskula, J.C.; Bonneau, M.; Krachmalnicoff, V.; Boiron, D.; Westbrook, C. I.; Kheruntsyan, K. V.

Annals of Operations Research
http://espace.library.uq.edu.au/view/UQ:190205
20091216T14:14:45Z

Anomalous power laws of spectral diffusion in quantum dots: A connection to luminescence intermittency
http://espace.library.uq.edu.au/view/UQ:219909
20101107T00:03:49Z
Plakhotnik, T; Fernee, MJ; Littleton, B; RubinszteinDunlop, H; Potzner, C; Mulvaney, P

Anomalous saturation effects due to optical spin depolarization in nitrogenvacancy centers in diamond nanocrystals
http://espace.library.uq.edu.au/view/UQ:279171
20120819T00:13:20Z
Chapman, Robert; Plakhotnik, Taras

A nonHopfian almost convex group
http://espace.library.uq.edu.au/view/UQ:163835
In this article we prove that an isometric multiple HNN extension of a group satisfying the falsification by fellow traveler property is almost convex. As a corollary, Wise's example of a CAT(0) nonHopfian group is almost convex.
20090211T10:05:37Z
Elder, Murray J.

A nonlinear numerical model for stratified Tsunami waves and its application
http://espace.library.uq.edu.au/view/UQ:58168
20070814T14:56:08Z
Imteaz, M.; Imamura, F.

A nonreductive N = 4 superconformal algebra
http://espace.library.uq.edu.au/view/UQ:271117
20120322T12:08:27Z
Rasmussen, J.

An openaccess online question generator with fully worked solutions
http://espace.library.uq.edu.au/view/UQ:252289
Mathematics staff at The University of Queensland have created an electronic question and solution generator that covers a wide range of fundamental mathematical, statistical and quantitative skills. This openaccess system allows teachers and/or students of all grades to create an unlimited number of questions covering over 100 topics, ranging from order of operations through to calculus and linear algebra. The beauty and originality of this flexible electronic framework is that fully worked solutions are also included. This paper outlines the process of developing and testing the question generator and discuss evidence of its effective implementation.
20110920T11:49:35Z
Jennings, Michael; Adams, Peter

An optically actuated surface scanning probe
http://espace.library.uq.edu.au/view/UQ:298968
We demonstrate the use of an extended, optically trapped probe that is capable of imaging surface topography with nanometre precision, whilst applying ultralow, femtoNewton sized forces. This degree of precision and sensitivity is acquired through three distinct strategies. First, the probe itself is shaped in such a way as to soften the trap along the sensing axis and stiffen it in transverse directions. Next, these characteristics are enhanced by selectively position clamping independent motions of the probe. Finally, force clamping is used to refine the surface contact response. Detailed analyses are presented for each of these mechanisms. To test our sensor, we scan it laterally over a calibration sample consisting of a series of graduated steps, and demonstrate a height resolution of ∼ 11 nm. Using equipartition theory, we estimate that an average force of only ∼ 140 fN is exerted on the sample during the scan, making this technique ideal for the investigation of delicate biological samples.
20130430T16:15:17Z
Phillips, D. B.; Gibson, G. M.; Bowman, R.; Padgett, M. J.; Hanna, S.; Carberry, D. M.; Miles, M. J.; Simpson, S. H.

An optical trap experiment to demonstrate fluctuation theorems in viscoelastic media
http://espace.library.uq.edu.au/view/UQ:298973
20130430T16:16:29Z
Carberry, D. M.; Baker, M. A. B.; Wang, G. M.; Sevick, E. M.; Evans, Denis J.

An optimal design for screening trials
http://espace.library.uq.edu.au/view/UQ:222309
20101124T13:47:18Z
Wang, Y. G.; Leung, D. H. Y.

An optomagnetomechanical quantum interface between distant superconducting qubits
http://espace.library.uq.edu.au/view/UQ:335573
20140729T00:40:44Z
Xia, Keyu; Vanner, Michael R.; Twamley, Jason

A Note on Gittins Indices for Pharmaceutical Research
http://espace.library.uq.edu.au/view/UQ:222308
20101124T13:47:13Z
Wang, Y. G.; Gittins, J.

A note on Kerr/CFT and free fields
http://espace.library.uq.edu.au/view/UQ:269836
20120314T11:41:00Z
Rasmussen, J.

A note on the existence and uniqueness of a bounded meanreverting process
http://espace.library.uq.edu.au/view/UQ:185157
20091022T13:23:08Z
Lesmono, D.; Pollett, P. K.; Tonkes, E. J.; Burrage, K.

A note on the HopfStiefel function
http://espace.library.uq.edu.au/view/UQ:268226
We give a short elementary proof for a formula for the HopfStiefel function that was found recently by Plagne via additive number theory.
20120223T15:59:48Z
Karolyi, Gyula

A note on the pathdiscrepancy of trees
http://espace.library.uq.edu.au/view/UQ:267822
20120217T16:14:18Z
Barany, I.; Karolyi, Gyula

A novel approach for biomarker selection and the integration of repeated measure experiments from two platforms
http://espace.library.uq.edu.au/view/UQ:309712
20130919T12:48:12Z
Liquet, B.; Le Cao, K.; Hocini, H.; Thiebaut, R.

A novel breeding programme for improved growth in barramundi Lates calcarifer (Bloch) using foundation stock from progenytested parents
http://espace.library.uq.edu.au/view/UQ:251770
Rapid genetic gains for growth in barramundi (Lates calcarifer) appear achievable by starting a breeding programme using foundation stock from progeny tested broodstock. The potential gains of this novel breeding design were investigated using biologically feasible scenarios tested with computer simulation models. The design involves the production of a large number of fullsib families using artificial mating which are compared in common growout conditions. The estimated breeding values of their paternal parents are calculated using a binomial probit analysis to assess their suitability as foundation broodstock. The programme can theoretically yield faster rates of genetic gain compared to other breeding programmes for aquaculture species. Assuming a heritability of 0.25 for growth, foundation broodstock evaluated in two years had breeding values for faster growth ranging from 21% to 51% depending on the genetic diversity of stock under evaluation. As a comparison it will take between nine and twentytwo years to identify broodstock with similar breeding values in a contemporary barramundi breeding programme.
20110911T21:28:14Z
Macbeth, Gilbert Michael; Palmer, Paul John

A novel protocolauthentication algorithm ruling out a maninthe middle attack in quantum cryptography
http://espace.library.uq.edu.au/view/UQ:190441
In this work we review the security vulnerability of quantum cryptography with respect to "maninthemiddle attacks" and the standard authentication methods applied to counteract these attacks. We further propose a modified authentication algorithm which features higher efficiency with respect to consumption of mutual secret bits.
20091218T13:12:19Z
Peev, M.; Nölle, M.; Maurhardt, O.; Lorünser, T.; Suda, M.; Poppe, A.; Ursin, R.; Fedrizzi, A.; Zeilinger, A.

An overview of Calanus helgolandicus ecology in European waters
http://espace.library.uq.edu.au/view/UQ:112357
We review current knowledge and understanding of the biology and ecology of the calanoid copepod Calanus helgolandicus in European waters, as well as provide a collaborative synthesis of data from 18 laboratories and 26 sampling stations in areas distributed from the northern North Sea to the Aegean and Levantine Seas. This network of zooplankton timeseries stations has enabled us to collect and synthesise seasonal and multiannual data on abundance, body size, fecundity, hatching success and vertical distribution of C helgolandicus. An aim was to enable comparison with its congener Calanus finmarchicus, which has been studied intensively as a key component of European and north east Atlantic marine ecosystems. C finmarchicus is known to overwinter at depth, whereas the lifecycle of C helgolandicus is less well understood. Overwintering populations of C helgolandicus have been observed off the Atlantic coast between 400 and 800 m, while in the Mediterranean there is evidence of significant deepwater populations at depths as great as 4200 m. The biogeographical distribution of C helgolandicus in European coastal waters covers a wide range of habitats, from open ocean to coastal environments, and its contribution to mesozooplankton biomass ranges from 6 % to 93 %. Highest abundances were recorded in the Adriatic and off the west coast of Spain. C helgolandicus is generally found in 920 degrees C water, with maximum abundances from 1317 degrees C. In contrast, C finmarchicus is found in cooler water between 0 and 15 degrees C, with peak abundances from 0 to 9 degrees C. As water has warmed in the North Atlantic over recent decades, the range of C. helgolandicus and its abundance on the fringes of its expanding range have increased. This review will facilitate development of population models of C. helgolandicus. This will not only help answer remaining questions but will improve our ability to forecast future changes, in response to a warming climate, in the abundance and distribution of this important species. (c) 2005 Elsevier Ltd. All rights reserved.
20070919T17:31:53Z
Bonnet, Delphine; Richardson, Anthony; Harris, Roger; Hirst, Andrew; Beaugrand, Gregory; Edwards, Martin; Ceballos, Sarah; Diekman, Rabea; LopezUrrutia, Angel; Valdes, Luis; Carlotti, François; et al.

Antireflection coating for improved optical trapping
http://espace.library.uq.edu.au/view/UQ:170393
An antireflection coating improves the trapping of highindex particles in optical tweezers by reducing the scattering force. This can allow the strong trapping of highindex particles that cannot normally be trapped, and the use of lower numerical aperture objectives while still obtaining strong trapping. The improvement is not overly sensitive to the refractive index or thickness of the coating.
20090318T10:33:02Z
Hu, Ying; Nieminen, Timo A.; Heckenberg, Norman R.; RubinszteinDunlop, Halina

Antiselfdual connections and their related flow on 4manifolds
http://espace.library.uq.edu.au/view/UQ:163424
In this paper, we establish the existence of the maximal time for a smooth solution to the antiselfdual (ASD) flow in vector bundles over a 4dimensional compact Riemannian manifold M and present a different proof of the Taubes’ existence theorem on antiselfdual connections on 4manifolds.
20090209T14:00:14Z
Hong, M.C.; Yu, Z.

Antisymmetrization reveals hidden entanglement
http://espace.library.uq.edu.au/view/UQ:186152
Twophoton antibunching at a beamsplitter is only possible if the photons are entangled in a specific state, antisymmetric in the spatial modes. Thus, observation of antibunching is an indication of entanglement in a degree of freedom, which might not be easily accessible in an experiment. We experimentally demonstrate this concept in the case of the interference of two frequencyentangled photons with continuous frequency detunings. The principle of antisymmetrization of the spatial part of a wavefunction and subsequent detection of hidden entanglement via antibunching at a beamsplitter may facilitate the observation of entanglement in other systems, like atomic ensembles or Bose–Einstein condensates. The analogue for fermionic systems would be to observe bunching.
20091115T00:01:25Z
Fedrizzi, Alessandro; Herbst, Thomas; Aspelmeyer, Markus; Barbieri, Marco; Jennewein, Thomas; Zeilinger, Anton

An ultrabright atom laser
http://espace.library.uq.edu.au/view/UQ:327278
20140331T08:39:42Z
Bolpasi, V.; Efremidis, N. K.; Morrissey, M. J.; Condylis, P. C.; Sahagun, D.; Baker, M.; von Klitzing, W.

An upper limit to the dry merger rate at 〈z〉 ∼0.55
http://espace.library.uq.edu.au/view/UQ:194323
20100131T00:06:19Z
DE Propris, R; Driver, SP; Colless, M; Drinkwater, MJ; Loveday, J; Ross, NP; BlandHawthorn, J; York, DG; Pimbblet, K

ANZIAM Journal
http://espace.library.uq.edu.au/view/UQ:94586
20070823T14:40:27Z

A padic supercongruence conjecture of van Hamme
http://espace.library.uq.edu.au/view/UQ:190974
20091223T15:20:09Z
Mortenson, Eric

A parallel implementation on GPUs of ADI finite difference methods for parabolic PDEs with applications in finance
http://espace.library.uq.edu.au/view/UQ:339905
20140917T16:37:18Z
Dang, D. M.; Christara, C. C.; Jackson, K. R.

A PDE pricing framework for crosscurrency interest rate derivatives with target redemption features
http://espace.library.uq.edu.au/view/UQ:340869
We propose a general framework for efficient pricing via a partial differential equation (PDE) approach for exotic crosscurrency interest rate (IR) derivatives, with strong emphasis on longdated foreign exchange (FX) IR hybrids, namely Power Reverse Dual Currency (PRDC) swaps with a FX Target Redemption (FXTARN) provision. The FXTARN provision provides a cap on the FXlinked PRDC coupon amounts, and once the accumulated coupon amount reaches this cap, the underlying PRDC swap terminates. Our PDE pricing framework is based on an auxiliary state variable to keep track of the total accumulated PRDC coupon amount. Finite differences on uniform grids and the Alternating Direction Implicit (ADI) method are used for the spatial and time discretizations, respectively, of the modeldependent PDE corresponding to each discretized value of the auxiliary variable. Numerical examples illustrating the convergence properties of the numerical methods are provided.
20141001T11:55:00Z
Christara, Christina C.; Dang, Duy Minh; Jackson, Kenneth R.; Lakhany, Asif

A phenomenological model of the superconducting state of the Bechgaard salts
http://espace.library.uq.edu.au/view/UQ:172870
We present a group theoretical analysis of the superconducting state of the Bechgaard salts, e.g., (TMTSF)2PF6 and (TMTSF)2ClO4 (TMTSF: tetramethyltetraselenafulvalene). We show that there are eight symmetry distinct superconducting states. Of these, only the (fully gapped, even frequency, odd parity, triplet) 'polar state' is consistent with the full range of the experiments on the Bechgaard salts. The gap function of the polar state is , where ψuk may be any odd parity function that is translationally invariant. This analysis also predicts that a phase transition, between two superconducting phases, occurs in weak magnetic fields.
20090331T12:56:21Z
Powell, B. J.

A phosphorescent poly(dendrimer) with increased viscosity for solutionprocessed OLED devices
http://espace.library.uq.edu.au/view/UQ:217108
20100926T00:01:43Z
Levell, Jack W.; Gunning, Jack P.; Burn, Paul L.; Robertson, Jeremy; Samuel, Ifor D. W.

A photondriven micromotor can direct nerve fibre growth
http://espace.library.uq.edu.au/view/UQ:265649
Axonal pathfinding is important in the development of the nervous system, nerve repair and nerve regeneration. The behaviour of the growth cone at the tip of the growing axon determines the direction of axonal growth and migration. We have developed an opticalbased system to control the direction of growth of individual axons (nerve fibres) using laserdriven spinning birefringent spheres. One or two optical traps position birefringent beads adjacent to growth cones of cultured goldfish retinal ganglion cell axons. Circularly polarized light with angular momentum causes the trapped bead to spin. This creates a localized microfluidic flow generating an estimated 0.17 pN shear force against the growth cone that turns in response to the shear. The direction of axonal growth can be precisely manipulated by changing the rotation direction and position of this optically driven micromotor. A physical model estimating the shear force density on the axon is described.
20120122T12:44:59Z
Wu, Tao; Nieminen, Timo A.; Mohanty, Samarendra; Miotke, Jill; Meyer, Ronald L.; RubinszteinDunlop, Halina; Berns, Michael W.

A photonic quantum gate based on electrically controlled strong cavity coupling between a single nanocrystal quantum dot and an ultrahigh Q silica microcavity
http://espace.library.uq.edu.au/view/UQ:247891
We investigate the use of nanocrystal quantum dots as a versatile quantum bus element for preparing various quantum resources for use in photonic quantum technologies. The ability to Stark tune nanocrystal quantum dots allows an important degree of control over the cavity QED interaction. Using this property along with the biexciton transition, we demonstrate a photonic CNOT interaction between two logical photonic qubits comprising two cavity field modes each. We find the CNOT interaction to be a robust generator of photonic Bell states, even with relatively large biexciton losses.These results are discussed in light of the current stateoftheart of both microcavity fabrication and recent advances in nanocrystal quantum dot technology. Overall, we find that such a scheme should be feasible in the near future with appropriate refinements to both nanocrystal fabrication technology and microcavity design. Such a gate could serve as an active element in photonicbased quantum technologies.
20110908T22:58:56Z
Fernee, Mark J.; RubinszteinDunlop, Halina

A PoincareBirkhoffWitt commutator lemma for Uq[gl(m vertical bar n)]
http://espace.library.uq.edu.au/view/UQ:64328
We present and prove in detail a PoincareBirkhoffWitt commutator lemma for the quantum superalgebra Uq[gl(m\n)]. (C) 2003 American Institute of Physics.
20070814T19:05:17Z
De Wit, D

A polynomial embedding of pairs of orthogonal partial Latin squares
http://espace.library.uq.edu.au/view/UQ:330488
20140520T02:19:21Z
Donovan, Diane M.; Sule Yazici, Emine

Apparent Violation of the WiedemannFranz Law near a Magnetic Field Tuned MetalAntiferromagnetic Quantum Critical Point
http://espace.library.uq.edu.au/view/UQ:173706
The temperature dependences of the interlayer electrical and thermal resistivity in a layered metal are calculated for Fermi liquid quasiparticles which are scattered inelastically by twodimensional antiferromagnetic spin fluctuations. Both resistivities have a linear temperature dependence over a broad temperature range. Extrapolations to zero temperature made from this linearT range give values that appear to violate the WiedemannFranz law. However, below a lowtemperature scale, which becomes small close to the critical point, a recovery of this law occurs. Our results describe recent measurements on CeCoIn5 near a magnetic fieldinduced quantum phase transition. Hence, the experiments do not necessarily imply a nonFermi liquid ground state.
20090403T13:09:28Z
Smith, M. F.; McKenzie, Ross H.

Application of Bayesian model averaging to measurements of the primordial power spectrum
http://espace.library.uq.edu.au/view/UQ:230553
20110228T12:00:07Z
Parkinson, David; Liddle, Andrew R.

Application of gene shaving and mixture models to cluster microarray gene expression data
http://espace.library.uq.edu.au/view/UQ:134938
Researchers are frequently faced with the analysis of microarray data of a relatively large number of genes using a small number of tissue samples. We examine the application of two statistical methods for clustering such microarray expression data: EMMIXGENE and GeneClust. EMMIXGENE is a mixturemodel based clustering approach, designed primarily to cluster tissue samples on the basis of the genes. GeneClust is an implementation of the gene shaving methodology, motivated by research to identify distinct sets of genes for which variation in expression could be related to a biological property of the tissue samples. We illustrate the use of these two methods in the analysis of Affymetrix oligonucleotide arrays of wellknown data sets from colon tissue samples with and without tumors, and of tumor tissue samples from patients with leukemia. Although the two approaches have been developed from different perspectives, the results demonstrate a clear correspondence between gene clusters produced by GeneClust and EMMIXGENE for the colon tissue data. It is demonstrated, for the case of ribosomal proteins and smooth muscle genes in the colon data set, that both methods can classify genes into coregulated families. It is further demonstrated that tissue types (tumor and normal) can be separated on the basis of subtle distributed patterns of genes. Application to the leukemia tissue data produces a division of tissues corresponding closely to the external classification, acute myeloid meukemia (AML) and acute lymphoblastic leukemia (ALL), for both methods. In addition, we also identify genes specific for the subgroup of ALLTcell samples. Overall, we find that the gene shaving method produces gene clusters at great speed; allows variable cluster sizes and can incorporate partial or full supervision; and finds clusters of genes in which the gene expression varies greatly over the tissue samples while maintaining a high level of coherence between the gene expression profi les. The intent of the EMMIXGENE method is to cluster the tissue samples. It performs a filtering step that results in a subset of relevant genes, followed by gene clustering, and then tissue clustering, and is favorable in its accuracy of ranking the clusters produced.
20080409T14:10:46Z
Do, K. A.; McLachlan, G. J.; Bean, R. W.; Wen, S.

Application of the bootstrap approach to the choice of dimension and the a parameter in the SIRa method.
http://espace.library.uq.edu.au/view/UQ:309592
20130917T12:39:43Z
Liquet, Benoit; Saracco, Jerome

Applications of maximum principles to dynamic equations on time scales
http://espace.library.uq.edu.au/view/UQ:204292
20100425T00:03:22Z
Stehlik, P; Thompson, B

Applied dimensional problems in mathematics courses: how smallscale partnerships across disciplines can improve mathematical problemsolving skills of engineering students
http://espace.library.uq.edu.au/view/UQ:329152
20140502T12:48:46Z
McCredden, Julie E.; O'Brien, Katherine R.; Roberts, Tony P.

Applying matrix product operators to model systems with longrange interactions
http://espace.library.uq.edu.au/view/UQ:167097
An algorithm is presented which computes a translationally invariant matrix product state approximation of the ground state of an infinite onedimensional (1D) system. It does this by embedding sites into an approximation of the infinite “environment” of the chain, allowing the sites to relax and then merging them with the environment in order to refine the approximation. By making use of matrix product operators, our approach is able to directly model any longrange interaction that can be systematically approximated by a series of decaying exponentials. We apply these techniques to compute the ground state of the HaldaneShastry model [Phys. Rev. Lett. 60, 635 (1988) and Phys. Rev. Lett. 60, 639 (1988)] and present the results.
20090311T11:32:33Z
Crosswhite, Gregory M.; Doherty, A. C.; Vidal, Guifre

Approach to frequency estimation in selfmixing interferometry: multiple signal classification
http://espace.library.uq.edu.au/view/UQ:303486
Based on the nature of selfmixing signals, we propose the use of the multiple signal classification (MUSIC) algorithm in place of the fast Fourier transform (FFT) for processing signals obtained from selfmixing interferometry (SMI).We apply this algorithm to two representative SMI measurement techniques:range finding and velocimetry. Applying MUSIC to SMI range finding, we find its signaltonoise ratio performance to be significantly better than that of the FFT, allowing for more robust, longerrange measurement systems. We further demonstrate that MUSIC enables a fundamental change in how SMI Doppler velocity measurement is approached, letting one discard the complex fitting procedure and allowing for a realtime frequency estimation process.
20130623T00:14:00Z
Nikolic, Milan; Jovanovic, Dejan P.; Lim, Yah Leng; Bertling, Karl; Taimre, Thomas; Rakic, Aleksandar D.

Approximate and exact modeling of optical trapping
http://espace.library.uq.edu.au/view/UQ:236630
Approximate methods such a Rayleigh scattering and geometric optics have been widely used for the calculation of forces in optical tweezers. We investigate their applicability and usefulness, comparing results using these approximate methods with exact calculations. © 2010 SPIE.
20110315T15:04:51Z
Nieminen, Timo A.; Alexander Stilgoe; Heckenberg, Norman R.; RubinszteinDunlop, Halina

Approximately uniform online checkpointing with bounded memory
http://espace.library.uq.edu.au/view/UQ:333719
In many complex computational processes one may want to store a sample of the process' history for later use by placing checkpoints. In this paper we consider the problem of maintaining, in an online fashion, a collection of k checkpoints as an approximately uniformly spaced sample in the history of a continuoustime process. We present deterministic algorithms tailored for small values of k and a general one for arbitrary k. The algorithms are proven to be close to optimum for several different measures.
20140627T18:43:20Z
Ahlroth, Lauri; Pottonen, Olli; Schumacher, André

Approximate record matching using hash grams
http://espace.library.uq.edu.au/view/UQ:268046
Accurately identifying duplicate records between multiple data sources is a persistent problem that continues to plague organizations and researchers alike. Small inconsistencies between records can prevent detection between two otherwise identical records. In this paper, we present a new probabilistic hgram (hash gram) record matching technique by extending traditional ngrams and utilizing scale based hashing for equality testing. hgram matching highly reduces the number of comparisons to be performed for duplicate record detection applicable to a variety of data types and data sizes by transforming data into its equivalent numerical realities. One of the key features of hgram matching is that it is highly extensible providing more intuitive and flexible results. With the sampling technique in place, our method can be applied on variable size databases to perform data linkage and probabilistic results can be quickly obtained. We have extensively evaluated hgram matching on large samples of realworld data and the results show higher level of accuracy as well as reduction in required time when compared with existing techniques.
20120221T17:58:00Z
Gollapalli, Mohammed; Li, Xue; Wood, Ian; Governatori, Guido

Approximating the tail of the Anderson–Darling distribution
http://espace.library.uq.edu.au/view/UQ:272812
20120416T15:46:12Z
Grace, Adam W.; Wood, Ian A.

A prescription and fast code for the longterm evolution of star clusters  II. Unbalanced and core evolution
http://espace.library.uq.edu.au/view/UQ:320214
We introduce version two of the fast star cluster evolution code Evolve Me A Cluster of StarS (EMACSS). The first version (Alexander and Gieles) assumed that cluster evolution is balanced for the majority of the life cycle, meaning that the rate of energy generation in the core of the cluster equals the diffusion rate of energy by twobody relaxation, which makes the code suitable for modelling clusters in weak tidal fields. In this new version, we extend the model to include an unbalanced phase of evolution to describe the precollapse evolution and the accompanying escape rate such that clusters in strong tidal fields can also be modelled. We also add a prescription for the evolution of the core radius and density and a related cluster concentration parameter. The model simultaneously solves a series of firstorder ordinary differential equations for the rate of change of the core radius, halfmass radius and the number of member stars N. About two thousand integration steps in time are required to solve for the entire evolution of a star cluster and this number is approximately independent of N.We compare the model to the variation of these parameters following from a series of direct Nbody calculations of singlemass clusters and find good agreement in the evolution of all parameters. Relevant timescales, such as the total lifetimes and core collapse times, are reproduced with an accuracy of about 10 per cent for clusters with various initial halfmass radii (relative to their Jacobi radii) and a range of different initial N up to N = 65 536. The current version of EMACSS contains the basic physics that allows us to evolve several cluster properties for singlemass clusters in a simple and fast way. We intend to extend this framework to include more realistic initial conditions, such as a stellar mass spectrum and massloss from stars. The EMACSS code can be used in star cluster population studies and in models that consider the coevolution of (globular) star clusters and largescale structures.
20131231T00:58:41Z
Gieles, Mark; Alexander, Paul E. R.; Lamers, Henny J. G. L. M.; Baumgardt, Holger